Investigation of optimal hydrogen sensing performance in semiconducting carbon nanotube network transistors with palladium electrodes

Abstract

The work function of palladium (Pd) is known to be sensitive to hydrogen (H2) via the formation of a surface dipole layer or Pd hydride. One approach to detect such a change in the work function is based on the formation of a Schottky barrier between Pd and a semiconductor. Here, we demonstrate a H2 sensor operable at room temperature by assembling solution-processed, pre-separated semiconducting single-walled carbon nanotube (SWNT) network bridged by Pd source/drain (S/D) electrodes in a configuration of field-effect transistors (FETs) with a local back-gate electrode. To begin with, we observed that the H2 response of the fabricated SWNT FETs can be enhanced in the linear operating regime, where the change in the work function of the Pd S/D electrodes by H2 can be effectively detected. We also explore the H2 responses in various SWNT FETs with different physical dimensions to optimize the sensing performance.